In the past, a UV irradiation device has been widely used in fluorescence reaction observations in the medical or biological field, for sterilization, adhesion of electronic components, curing of UV curable resins and inks, and the like. In particular, a high pressure mercury lamp, a metal-halide lamp, or the like are used as a lamp light source of a UV irradiation device which is used when curing the UV curable resin used when adhering small sized components or the like in a field of electronic components or the like, curing UV curable ink which is used in the printing field, or the like.
In recent years, a movement toward adopting UV light emitting elements which have a relatively long life, are energy saving, and are able to suppress generation of ozone as a lamp light source has become active, since a reduction in load on the global environment is demanded worldwide.
Meanwhile, since generation of heat due to driving of the UV light emitting element is relatively high, for example as disclosed in Patent Literature 1, a technology has been proposed in which a heat radiation member is provided in a light emitting element mounting substrate, and heat from the light emitting element is effectively radiated.
However, since the demand for improved illuminance of light emission has gradually become stronger, and there is a tendency for the number of mounted light emitting elements to increase, a heat radiation structure in which heat can be effectively radiated has become desirable.